widowmaker
What does widowmaker mean?
A loose limb, broken treetop, or dead branch hung up in the canopy that can fall without warning — usually onto whoever's working below. One of the top killers on wildland fires and a constant hazard during mop-up in burned timber, when fire-weakened trees start dropping pieces hours or days later. Lookouts are posted specifically to call them out; you don't sit, eat, or sleep under one.
Origin
Logging and forestry slang dating to at least the late 19th century; carried into wildland firefighting vocabulary and codified in the NWCG glossary.